title: Effects of prolonged, purine-free total parenteral and enteral nutrition on urate homeostasis in man.
abstract: The influence on human urate homeostasis of prolonged, totally purine-free nutritional support, using total parenteral (TPN) or elemental enteral (EN) nutrition, is not well known. In a prospective study, we measured weekly serum uric acid, renal urate excretion and clearance, together with parameters of hydration, in 58 normally hydrated patients receiving prolonged (15 to 170 days) purine-free TPN (30 patients) or EN (28 patients) for various gastrointestinal disorders. A marked, early and sustained decrease (p less than 0.001) in serum uric acid was observed in TPN (155 +/- 9 mumol/l at day 7 versus 318 +/- 13 mumol/l before nutrition, mean +/- SEM) as well as in EN patients (192 +/- 11 mumol/l at day 7 versus 320 +/- 16 mumol/l before nutrition), together with a significant (p less than 0.01) rise in renal urate clearance. The urate clearance/glomerular filtration rate ratio increased significantly, while there was no significant change in natremia or plasma osmolarity. Serum urate and urate clearance returned to normal within 8 days of refeeding with a normally purine-containing diet. Replacement of TPN by EN or vice versa, or substitution of glucose by fructose resulted in no change in hypouricemia. A 4-day oral supply of purines (125 mg/day) in EN patients was associated with a 53% rise (p less than 0.01) in serum urate. We conclude that prolonged, purine-free TPN and elemental EN are a new cause of marked hypouricemia which is mainly due to increased urate clearance, the mechanism of the latter is still poorly known, but is not related to extracellular volume expansion.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004750:Enteral Nutrition; D005260:Female; D005632:Fructose / Q000008:administration & dosage; D005767:Gastrointestinal Diseases / Q000628:therapy; D005919:Glomerular Filtration Rate; D005947:Glucose / Q000008:administration & dosage; D006706:Homeostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010288:Parenteral Nutrition; D010289:Parenteral Nutrition, Total; D011687:Purines / Q000008:administration & dosage*; D012964:Sodium / Q000097:blood; D013997:Time Factors; D014527:Uric Acid / Q000378:metabolism*
chemical_list: D011687:Purines; D014527:Uric Acid; D005632:Fructose; D012964:Sodium; D005947:Glucose